1. Field of the Invention
The present invention relates to a deformable sensor system that can be used for pressure-distribution sensors, and the like, for instance.
2. Description of the Related Art
Conventionally, as for a pressure-distribution sensor, there have been those which are set forth in Japanese Unexamined Patent Publication (KOKAI) Gazette No. 6-281,516, Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2006-284,404 and Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2003-98,022.
In the pressure-distribution sensor that is set forth in Japanese Unexamined Patent Publication (KOKAI) Gazette No. 6-281,516, electrodes, in which a large number of detector points are formed as a matrix shape, are disposed on both surfaces of a pressure-sensitive conductive elastomer sheet, or on one of the surfaces thereof. And, utilizing the fact that the electric resistivity of the pressure-sensitive conductive elastomer sheet's deformed part changes in the case where the pressure-sensitive conductive elastomer has received a pressure, a position in the pressure-sensitive conductive elastomer sensor, position which has received the pressure, is detected by electrodes that are adjacent to the said deformed part.
Moreover, in the pressure-distribution sensor that is set forth in Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2006-284,404, an electrode is formed on each of a first sensor sheet and a second sheet, which are to be laminated, respectively. And, utilizing the fact that the electric resistivity declines in the case where the sensor sheets have received a pressure, a position of the pressure application is detected by the electric resistivity between the electrodes of the respective sensor sheets. Moreover, also in the pressure-distribution sensor that is set forth in Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2003-98,022, electrodes are disposed on the rear-surface side of a pressure-receiving surface in substantially the same manner as the aforementioned literatures.
Specifically, in all of the pressure-distribution sensors that are set forth in the aforementioned literatures, electrodes for carrying out detection are disposed on their entire pressure-receiving surfaces. Thus, since the electrodes are disposed on the entire pressure-receiving surface, the number of the electrodes have become very enormous when enlarging the pressure-receiving surface. If such is the case, there has been such a problem that, since the wiring becomes enormous, the mountability has become poor and further the expanding/contracting property of sensor per se has been impaired.
And so, studies for solving this problem have been underway; and an achievement of the studies was made public in “‘A tactile sensor based on Inverse-problem Theory: the Principle,’ written by Akihiko Nagakubo and Yasuo Kuniyoshi, in 24th Academic Lecture Meeting by the Robotics Society of Japan (from Sep. 14 through 16, 2004).”In the pressure-distribution sensor that is set forth in this paper, a plurality of electrodes are installed to the outer periphery of a pressure-sensitive rubber sheet, and a resistance distribution is estimated in the pressure-sensitive rubber sheet's inside region using such a technology as “EIT” (Electric Impedance Tomography) that is based on an inverse-problem theory. And, in this inverse-problem analysis, using the least-squares method, and the like, is set forth, for instance.
However, in the inverse-problem analysis, since there is no uniqueness in solution, it is not possible to estimate an appropriate pressure distribution in the case of obtaining it based on the least-square method that is free of any restrictions.